Most passenger cars which are manufactured at present are loaded with so-called air bags for a driver's seat and a front passenger seat in order to ensure safety of the occupants by rapidly inflating bag bodies between the occupants and an automobile interior structure when the front of the automobile collides (collides head-on) with another automobile or an obstacle.
In recent years, in order to protect heads of occupants not only at the time of a head-on collision but also at a time of a side of an automobile colliding with another automobile or an obstacle (lateral collision), curtain bag systems begin to be really loaded, which inflate curtain bags stored by being folded in ceiling portions and pillar portions above side window sections of the automobiles to cover the side window sections at the time of collision.
Conventionally, the curtain bag shown in Patent Document 1 is known as one example of a curtain bag. The curtain bag of Patent Document 1 is configured in such a way that two pieces of coated fabric are joined to each other at a peripheral joining section which is provided at a peripheral edge to define an outer peripheral shape of the bag, and inner joining section provided at an inner side of the peripheral joining section, as shown in FIG. 13. The inner joining section defines the inflated shape of an inflation section (section to be inflated by introduction of a gas), and is provided to be a straight line, a curved line, or a U-shaped configuration with both of former lines being combined which are continuing to the peripheral joining section. Further, the curtain bag shown in Patent Document 1 has a gas inflow port to which a gas generator (inflator) is connected, in an upper portion at a rear side of the curtain bag.
A curtain bag shown in Patent Document 2 is known as a new curtain bag. The curtain bag of Patent Document 2 is configured in such a way that two pieces of fabric are joined at a peripheral joining section which is provided at a peripheral edge to define an outer peripheral shape of the bag, and a plurality of dot-shaped inner joining sections which are provided at an inner side of the peripheral joining section and are independent from one another. The curtain bag has the feature of smooth and quick inflow of a gas from a gas generator (inflator) and fast deployment by being provided with the dot-shaped inner joining sections.
In formation of the above described peripheral joining section and inner joining sections, a method by machine-sewing, and a method which forms a joining section by interlacing weaving yarns with each other in a predetermined position and into a predetermined shape at a weaving stage by using a loom loaded with a Jacquard loom (hereinafter, referred to as an OPW method) are put to practical use. Further, there is a type having a gas inflow port at an upper portion of a bag. Further, there are two curtain bag systems: one simply protects occupants only shortly after a lateral collision occurs (first impact corresponding type) and the other also considers the protection of the occupants in case where an automobile rolls over after a lateral collision (roll over corresponding type).